Can I upgrade the RAM of the MacBook Pro 13' Retina from 8gb to 16gb after/during purchase? - Quora
Apple MacBook Pro with Retina Display (13-inch, 2015) review: Apple's 2015 MacBook Pro is still around for those who want fewer dongles - CNET
Upgrading RAM in Your MacBook Pro 13" or 15" : 19 Steps (with Pictures) - Instructables
MacBook Pro | Core i5 2.7 GHz | 13 Inch | Early 2015 Upgraded Storage and RAM | eBay
A-Tech 8GB Kit (2x4GB) RAM for Apple MacBook Pro (Mid 2012), iMac (Late 2012, Early/Late 2013, Late 2014, Mid 2015), Mac Mini (Late 2012) | DDR3 1600MHz PC3-12800 SODIMM 204-Pin Memory Upgrade at Amazon.com
How to Upgrade the SSD in a 13-inch MacBook Pro w/ Retina display (Late 2013 - Early 2015) on Vimeo
16GB MacBook Pro RAM Upgrade (2011/2012/2013) - YouTube